The effect of temperature and CO2 on the development of pink stem borer on maize

Pink Stem Borer, Sesamia inferens Walker (Lepidoptera: Noctuidae) incidence has increased on graminaceous crops in the north-western plains of India during recent years. To understand the effect of climate change on the northward spread of the pest, studies on the growth and development of S. inferens on maize (Zea mays L.) were planned with combinations of temperature and CO2. The combinations were 27: 22 degrees C and 375 ppm of CO2, 32: 26 degrees C and 375 ppm of CO2, 27: 22 degrees C and 450 ppm of CO2 and 32: 26 degrees C and 450 ppm of CO2. Various developmental parameters of S. inferens were analyzed using analysis of variance for the main effects of temperature and CO2 and their interactions. At elevated temperature, the growth of egg, larval and pupal stages were faster and the developmental period decreased by 30.9%. At elevated CO2, the larval and pupal development delayed and there was 5.7% increase in developmental period. Both temperature and CO2 individually and in combination significantly influenced adult longevity. Adult longevity reduced 24.9% and 21.7% in male and female, respectively at elevated temperature. Whereas, at elevated CO2, adult longevity increased 7.6% in male and 6.8% in female, respectively. The fecundity was positively influenced (+10.8%) by elevated temperature and negatively (-14.4%) by elevated CO2. The effects of temperature and CO2 on the development of pink stem borer were opposite, with temperature being positive and predominant in influencing the biology of S. inferens. So, it is probable that the faster development of S. inferens on maize in the warm climate might slightly get mitigated by the adverse effect of elevated CO2. The overall effect of rapid development of pest population and damage on maize on large area basis needs to be further investigated.